3-methylene-cyclobutanes



' a of olefin to two moles of allene.

3-METHYLENE-CYCLOBUTANES Harry Norman Cripps, Hockessin, Del., assignorto E. I. du Pont de Nemours and Company, Wilmington, Del., a corporationof Delaware N Drawing. Application September 2, 1955 Serial No. 532,376

6 Claims. (Cl. 260-3463) This invention relates to cyclic organiccompounds. More particularly, it relates to new unsaturated cyclicorganic compounds having certain functional groups, and to a method fortheir preparation.

This is a continuation-in-part of U.S. application Serial No. 476,585,filed December 20, 1954 by H. N. Cripps, and now abandoned.

Unsaturated compounds have certain properties which make them useful invarious applications. One such property which is responsible for theirwidespread commercial use is the ability of many unsaturated compoundsto be polymerized to valuable high molecular weight products. While theknown polymers have many characteristics which are desirable for use invarious applications there are some applications in which polymershaving certain specific properties or combinations of properties wouldhave increased utility.

This invention has as an object the preparation of new unsaturatedcompounds which can be polymerized and copolymerized with otherpolymerizable monomers to form products of unusual or improvedproperties. A further object is the synthesis of new unsaturated cycliccompounds having certain functional groups which are useful as chemicalintermediates. Another object is the preparation of condensation polymerintermediates. Other objects of the invention will appear by aconsideration of the following description of certain embodimentsthereof. a

These objects are accomplished by the present invention of an adduct ofan allene having two hydrogen atoms on at least one of the terminalallene carbons with an equimolar amount of from one to two. moles of anolefin having an activating group on at least one of the doubly bondedcarbons. These products are of two classes: those from addition of onemole of olefin to one mole of allene, and those from addition of twomoles The products resulting from addition of one mole of the olefin toone mole of the allene are methylenecyclobutanes in which the annularcarbon opposite the one to which the methylene group is attached (i.e.,the carbon in the 3-position with the methylene group attached to thecarbon in the 1-position) carries an activating group, which activatinggroup is characterized in that it is united to one annular carbon of thecyclobutane ring by a carbon which is in turn attached to another atomby a multiple bond. A preferred group of the compounds of this class isthat in which any substituents on the cyclobutane ring, in addition tothe aforementioned activating group, are hydrocarbon or are activatinggroups of the type, defined above. Especially preferredmethylenecyclobutanes are those in which at least one of the car-2,914,541 Patented Nov. 24, T959 bons adjacent to the one carrying themethylene group is unsubstituted.

The products resulting from the addition of two moles of the olefin totwo moles of allene are A -octalins having an even number, from 2 m4, ofactivating groups on annular carbons, each activating grou being .on

singly bonded carbon separated by one carbon from doubly bonded carbonand there being the same number of activating groups on eachsix-membered ring, each carbon adjacent to the doubly'bonded carbonsbearing two hydrogens, the activating groups being attached to annularcarbons of the octalin nucleus by carbon attached by a multiple bond toanother ato A preferred group of the compounds of this class is that inwhich any remaining valences of nuclear carbon are satisfied byhydrogen, hydrocarbon groups, or activating groups of the type definedabove.

The process of this "invention is carried out by heating,

in the absence of a polymerization initiator, a mixture of an allenehaving at leastone of the terminal carbon atoms of the allene group,C='C='C unsubstituted and a substituted ethylene having an activatinggroup attached to one of the doubly bonded carbons of the ethyleniclinkage to a temperature of -250 C. The actiyating group in thesubstituted ethylene reactant is characterized in the same manner as theactivating group in the products defined above. That is, it, is-a groupattached to one ofthe olefinic carbons by a carbon atom that is in turnattached to another atom by a multiple bond. The reaction involving theformation of a methylenecyclobutane is illustrated by the followingequation for the reaction of allene with acrylonitrile:

The reaction involving the formation of a substituted A -octalin isillustrated by the following equations for the reaction of alleneacrylonitrile: J

Both classes of the'products of this invention are obtained from thealleneand'the substituted ethylene: under the general reactionconditions defined above; however, the yield of each type of product isinfluenced by the. particular reaction conditions employed. Best yieldsof the 'm'cthylenecyclobutane products are obtained when an excess,e.g., a' 100% excess, of the substituted ethylene reactant isemployed.On the other hand, best yields of the polysubstituted A -octalins areobtained when equimolar amounts of the reactants, or a'slight excess ofallene, are employed. 7

Preferably the reaction is carried out at a temperature of to 225 C.,and in the presence of an addition polymerization inhibitor. Within thebroad temperature operating range of 150 to 250 C., the lowertemperatures, i.e., 150 to 200 0., generally favor the reaction leadingto the formation of methylenecyclobutanes. Consequently, when bestyields of this class of product are desired, temperatures below 200 C.are generally preferred. n the other hand, operating temperatures above200 C. generally favor the formation of the polysubstituted A -octalins.Eonsequently, when best yields of this class of product are desired,temperatures above 200. 3C. are preferred. 7 v

The pressure under which this reaction is carried out is not critical.Good results are obtained when the reactants are heated in a closedcontainer under the autogenous pressure developed by the reactants underthe operating "conditions.

The reaction vessel can .beconstructed of any material which is inert tothe reactants and is capableof iwithstanding the operating'pressures.Reaction vessels made of glass, stainless steel and glass-lined steelare quite satisfactory. 9

The reaction time can be varied widely, times ranging from 2 to 24 hoursor more at 150 C. to 250 C. are operable. Very "good results areobtained in reaction periods ranging from 4 to 16 hours.

Reactants which are commercially available in the grades used forpolymerization are satisfactory for use in the process of thisinvention. However, best results are obtained when the 'allene isrelatively pure.

The process and products of this invention are illustrated in furtherdetail in the following examples, in which the proportions ofingredients are expressed in parts by weight unless otherwise noted.

Example I.-Preparati0n 0 3-methylenecyclobutanecarbonitrile A mixture of53.0 parts of acrylonitrile, 20.0 parts of allene and 1.0 part ofhydroquinone is heated in a closed stainless steel reaction vessel forldhours at 175 C. with continuous shaking. After cooling and bleedingoil the ,unreacted gaseous allene, the liquid residue amounts to 56.8parts. On distillation there is obtained 3.7 parts of3-methylenecyclobutanecarbonitrile, boiling point 70.5 72.5 C./29 mm.,and refractive index, 11 1.4600.

Analysis.-Calcd. for C H N: 'C, 77.3%; H, 7.6%; N, 15.1%; M01. wt.,93.1; Unsaturation (C=C),-0.0215 g. H /g. sample; Unsaturation (l C=Cand 1 GEN), 0.0645 g. H /g. sample. Found: C, 77.79%; 77.90%; H, 7.63%;7.65%; N, 14.39%; 14.41%; Mol. Wt. 93, 94.

Unsaturation (1C=C), 0.0236, 0.0230 g. H /g. sample.

Unsaturation (C=C and GEN), 0.0696, 0.0713 g. H lg. sample.

The infrared spectrum obtained on 3-methylenecyclobutanecarbonitrileshows absorption for methylene groups at 5.95 and 11.30 microns andabsorption for nitrile groups at 4.45 microns. Proton magnetic resonancemeasurements show a vinyl hydrogen peak, a CI-I hydrogen peak, and anHCX proton resonance (where Xis an electronegative group) of-relativeintensities 2:4:1 which are in agreement with the3-methylenecyclobutan'ecarbonitrile'stmcture. J x Y The3-methylenecyclobutanecarbonitrile of Example I is converted to3-methylcyclobutanecarboxylic acid by bydrogenation in thepresence ofpalladium oxide catalyst, followed by saponification with aqueousalcoholic sodium hydroxide. The free acid, after distillation through aneflicient fractionating column, boils at 108-1085 C./;18 mm. and hasarefractive index, 11 of 1.43501.435l.

Analysis.-Calcd. for C H o z C, 63.2%; H. 8.8%; NE. 114.2. Found: 0,63.60%; H, 8.97%; 1 4

Analysis.Calcd. for C H NO: N, 7.40%. N, 7.44%.

Example II.-Preparati0n of 3-methylenecyclobutanecarbonitrile and 2,6(or 7)-dicyan0-A -0cfalin Found:

A mixture of 53 .parts of acrylonitrile, 20 parts of allene and 1 partof hydroquinone is heated in a stainless steel reaction vessel atautogenous pressure for 16 hours at 200 C.' The reaction product isisolated as described in Example I, and there is obtained 20.9 parts(corresponding to a 45.5% yield based on the allene charged) of3-methylenecyclobutanecarbonitrile boiling at 59- 62 C./ 17.5 mm..Threis obtained as a residue from the distillation of the3:methylenecyclobutanecarbonitrile 11.1 parts of crude 2,6 (or 7)-dicyano-n -octalin. After sublimation and crystallation from a mixtureof 30 parts (by volume) of ethyl acetate and 25 parts of cyclohexane,there iso btained 5.4 parts of product melting at 143.5- 144.5 C.

Analysis.-Calcd. for 'C 'H Ngt' C, 77.3%; H, 7.6%; N, 15.1%; ,Mol. Wt.186.2; Quant. Hydg. (one C=C and two CEN), 0.0539 g. hydrogen/g. sample.Found: C, 76.35%; H, 7.51%; N, 15.04%; Moi. Wt. 175, Quant. Hydg.,0;0.499, 10.05 78 'g; hydrogen/ g. sample.

The-infrared absorption spectrum of this purified product shows a strongnitrile .band at 4.45 microns. The absenceof-the carbon-carbondouble'bond absorption is indicative of a symmetrical structure.

Saponification of 10 parts of the purified 2,6-(or 7)- dicyano-'A-octalin' withfsodi'um hydroxide'in an ethanol-water mixture,followedfby acidification, yields 13.7 parts {of isomeric acids. 7Fractional recrystallization of the crude'acids from mixtures'ofidim'et'hylforrnamide and water yieldstwo acids: acid .I, M.P.morethan 300 C.

(softens at 248-278 C.), "acid' H, M.P. '248-'250 C.

(softens at211 C.). v p I The methyl esters of these isomeric acids areprepared by heating 7.72 parts of the mixture of acids "obtained above,200 parts of anhydrous methanol, and 1 part of p-toluenesulfonic acidunder reflux for about '12 hours. The crude methyl esters, amounting to7.2 parts, corresponding to a yield of 83.2%, are isolated from thereaction mixture as a pale yellow viscous oil.

A heat-resistant glass reaction tube six inches long and one inch indiameter is packed with an intimate mixture lution to absorb the carbondioxide, and'the hydrogen; evolved is measured with a wet-test meter,2.2 'liters at" standard temperature and pressure being obtained. Thesolid product, amounting to. 1.55- parts, is identified as naphthaleneby a mixed melting point with an authenticspecimen; by odor and by itsultraviolet absorption spectrum.

Example l1I.Preparation of 3-methylenecyclobutanecarbonitrile and 2,6(or7)-dicyan0-A -0ctalin A mixture of 53 parts of acrylonitrile, 40 partsof allene, 88 parts of benzene, and 1 part of hydroquinone is heated ina stainless steel reaction vessel under autogenous pressure at 225 C.for four hours. After removal of the benzene and 14.1 parts of3-methylenecyclobutanecarbonitrile (B.P. 68-69.5 C./29 mm.) bydistillation, there remains 55.1 parts of crude 2,6(or 7)-dicyano-Aoctalin. After recrystallization from a mixture of .100 parts (byvolume) of ethyl acetateand 135'p'arts of cyclohexane, this productmelts at 139-140 C. 1

Example I V.-Preparation of 1-methyl-3-methylenecyclobutanecarbonitrileand 2,6 (or 7)-dicyah0-2,6(0r 7)"-dimethyl-A -octalin of allene and 2partsof hydroquinone is heated at 225 C. for 8 hours as described inExample 1. After Working up the reaction mixture as described in thatexample there is obtained 31.7parts. of. l methyl-3-meth'ylenecyclo-.

butanecarbonitrile, boiling at 58-58.5 C./21' mm., 71 1.4453.

Ana'lysin-Calcd. for C H N: C, 78.46%; H, 8.47%; N, 13.07%; Quant.Hydrog, 0.051 g. H /g. sample; Mol. Wt, 107.2. Found: C, 78.48%; H,8.54%; N, 12.51%; Quant. Hydrog., 0.059 g. H /g. sample; Mol. Wt. 95;0.060 g. H g. sample; Mol. Wt. 97. 1

The infrared spectrum shows terminal methylene absorption at 593 and11.25;, nitrile absonption at 4.48a and methyl absorption at 725 Theresidue from the distillation of1-methyl-3-methylenecyclobutanecarbonitrile contains 2,6(or 7)-dicyano-2,6(or 7)-dimethy1-A -octalin.

By substituting for the acrylonitrile and methacrylonitrile in ExamplesI, II, III and IV equivalent amounts of u-ethylacrylonitrile and maleicdinitrile, there can be obtained1-ethy1-3-methylenecyclobutanecarbonitrile and 2,6(or 7)-dicyano-2,6(or7)-diethyl-A -octalin, and 3- methylenecyclobutane-1,2-dicarbonitrileand 2,3,6,7'-tetracyano-A -octalin, respectively.

Example V.Copolymerization of 3-meth'ylehecycl0- butanecarbanitrile withstyrene Example VI.-Copolymerization of 3-methylenecycl0-butanecarbonitrile with maleic anhydride 'A mixture of 5.0 parts of3-methylenecyclobutanecarbonitrile, 5.28 parts of maleic anhydride, 66parts of benzene and 0.25 part of benzoyl peroxide is heated underreflux in an atmosphere of nitrogen. After minutes so A mixture of 201parts of methacrylonitrile, 20 parts ofrefiux, the reaction mixturebecomes turbid and in soluble polymer begins to precipitate. After twohours and 25 minutes of reflux, the reaction mixture is cooled anddiluted with 40' parts of acetone. The pale yellow polymer is separatedby'filtration, .washed with benzene and dried. dry polymer is a paleyellow powder which softens'at 202 C. but'does not melt at 300 C. Thepolymer dissolves readily in 14% NH OH to give a yellow solution. Thepolymer is insoluble in cold water but slowly dissolves in hotlwater.(about 1 part polymerv in parts of Water) in the presence of a smallamount of sulfuric acid. On analysis the dry polymer is found tocontain"60.3 2% carbon, 5.23% hydrogen, and 6.82%

, nitrogen. This nitrogen content indicates that the polymer contains45.2% of 3-methylenecyclobutanecarbonitrile.

Example VIL-Preparation of methyl 1-methyl-3-methylenecyclobatanecarboxylate A mixture of 100 parts of methylmethacrylate, 20 parts of allene and 1 part of hydroquinone is heated at200 C. for 8 hours in a closed reaction vessel of the type used in thepreceding examples. Distillation of the reaction mixture yields 20 parts(25% of theory) of methyl 1 methyl 3 -'methylenecyclobutanecarboxylateboiling at 50-54" C./ 16 mm. and having a refractive index, 21 of1.4411-1.4423. the product boils at 54-55 C./ 15 mm.

Analysis.-Calcd. for C H O C, 68.5%; Mol. wt. 140.2; Sap. Equiv., 140;Unsaturation, 0.0143 g. H /g. sample. Found: C, 68.89%; H, 8.73%; M01.wt. 137; Sap. Equiv., 140.9, 139.3; Unsaturation, 0.0155, 0.0147 g. H,;/g. sample.

The infrared spectrum shows ester carbonyl absorption at 5.75 micronsandterminal methylene absorption at 3.25, 5.95am 11.4microns.

Example VIM-Preparation of methyl S-methylenecyclobutanecarbbxylate Imo-cnoooon. orn=o=on5 one-onoo'ooni 0H,: H,

A mixture of 172 parts of methyl acrylate, 20 parts of allene and 1 partof phenothiazine is heated at 200 C. for 13 hours, by the procedure ofExample V-H. Most of the reaction product is a polymeric glassy mass. Ondistillation the reaction product yields 15.3 parts of liquid methyl3-methylenecyclobutanecarboxylate, B.'-P. 56-59 C./20-21 mm.

Analysis.Calcd. for C H O C, 66.63%; H, 7.98%; M01. wt., 126.2; Sap.Equ'iv., 126.2; Quant. Hydrog. 0.0158 g.H /g. sample- Found: C, 67.23%;H, 8.13%; M01. wt., 121; Sap. Equiv., 124.8. C, 67.04; H, 8.18; M01.wt., Sap. 'Equiv., 125.0; Quant'Hydrog, 0.0175 g. H /g. sample; 0.0181g. H /g. sample.

' ll H OOOCC C CH2 CH;

11 n mcoooo p ooooon,

H OCOOCH and/ or A mixture of 86.1 parts of methyl acrylate, 40 parts ofallene, 88 parts of benzene =and--2 parts of hydro- On redistillationthe major portion of v a M01. wt., 252. Found: C, 66.54%; H, 7.94%;M01.wt.

222. C, 66.53%; H, 8.04%; M01. wt. 226.

By replacing the methyl methacrylate and methyl acrylate of ExamplesVII, VIII and IX with equivalent quantities of n-butyl methacrylate andethyl acrylate, and following the procedures of those examples, therecan be obtained n-butyl 1-methy1-3-methylenecyclobutaneoarboxylate andethyl 3-methylenecyclobutanecarboxylate, respectively, and di-n-butyl2,6(or 7 )-dimethyl-A octalin-2,6(r 7 )-dicarboxylate and diethy1-A-octalin 2,6(0r 7 )-dicarb0xylate, respectively.

Example X.Preparation of diethyl S-metlzylenecyclobutane-1,Z-dicarboxylate and tetraethyl A P-0ctalin 2,3,6,7-tetracarboxylateHC-C O O C1115 H ram-0 0000.11. oak-0 0000113,

H 0H, OH, H CQHQOOCC/ (ul 3000002115 0 11 0061 C HCQ O.C2H5

A mixture of 86.1 parts of diethyl fumarate, parts of allene and 1 partof hydroquinone is heated under autogenous pressure at 200 C. for 13hours in areaction vessel of the type used in the preceding examples.Distillation of the reaction product yields 7.4 parts of diethyl3-methy1enecyclobutane-1,2-dicarb0xylate boiling at 76- 77" C./ 0.45 mm.and having a refractive index, n of 1.4497-1.4484.

Analysis.-Calcd. for C H O C, 62.5%; H, 7.60%; M01. wt., 212.2; Sap.Equiv., 106.1: Unsaturation, 0.0095 g. H /g. sample. Found: C, 62.65%;H, 7.87%; M01. wt., 205, 205; Sap. Equiv., 109; Unsaturation, 0.0111 g.H /g. sample; 0.0112 g. H /g. sample.

The residue from the above distillationof diethyl 3-methylenecyclobutane-1,2-dicarb0xy1ate is a solid amounting to 11.6parts. On recrystallization from methanol, white needles of tetraethyl A-0cta1in-2,3,6,7-tetracarboxylate, melting at 128-135 C., are obtained.

Analysis.Calcd. for C H O C, 62.25%; H, 7.60%; M01. Wt., 424; Sap.Equiv., 106.1. Found: C, 62.34%; H, 7.63%; M01. wt., 400; 405; Sap.Equiv., 106.

Example XI.Preparation of tetraethyl A -newlin- 2,3,6,7-tetracarboxylateH C O O C1H (321150 0 C C C CsHsOOCC U00 0 OjHs G COOCgHs G a CH:

. 8 ethanol, the solid residue gives white needles of tetraethyl A-0ctalin-2,3,6,7-tetracarb0xylate, melting at 140.5- 142.5 C.

Analysis.-Calcd. for C H O C, 62.25%; H, 7.60%; M01. wt., 424; Sap.Equiv., 106.1. Found: C, 62.71%; H, 7.66%; M01. wt., 379, 387; Sap.Equiv., 104.

The tetraethyl A -octa1in-2,3,6,7-tetracarb0xy1ate of this example isisomeric with that obtained from allene and diethylfumarate, asdescribed in Example X.

Example XIL-Preparation of diethyl 3-methylenecycl0-butane-LZ-diearboxylate A mixture of 457 parts of ethyl maleate, 40parts of allene and 1 part of hydroquinone is heated at autogenouspressure at 225 C. for 6 hours. After removing unreacted ethylmaleatefrom the reaction mixture by distillation under reduced pressure, theresidue is distilled through an eff cient fractionating column. There isobtained 17.9 parts of diethyl 3-methylenecycl0butane-1,2-dicarboxylate, boiling. at 119-122" C./ 10 mm., and hav ing a refractiveindex, r19 of 1.4484.

Analysis.-Calcd. for C H O C, 62.25%; H, 7.60%; M01. wt., 212.2; Sap.Equiv., 106.1. Found: C, 61.61%, 61.26%; H, 7.61%, 7.46%; M01. wt., 200,210; Sap. Equiv., 101.3, 101.5.

The residue from the distillation of the diethyl 3-methylenecyclobutane-1,2-dicarb0xy1ate amounts to 134 parts and is crudetetraethyi A -0etalin-2,3,6,7-tetracarboxylate.

When the diethyl fumarate and diethyl maleate of Examples X-XII arereplaced by equivalent quantities of diethyl methylenemalonate, therecan be obtained diethyl 3-methylenecycl0butane-1,l-dicarboxylate andtetraethyl A -0ctalin-2,2,6,6 (0r 7,7 -tetracarb0xylate.

Example XIIL-Preparation of 1-methylene-3,3-diphenyl- H2C=,' E: 5 5 Amixture of 39.8 parts of 1,1-diphenylethylene 10 parts of allene and 0.5partof hydroquinone is; heated for 8 hours at 200 C. under autogenouspressure in a reaction vessel of the type used in the precedingexamples.Distillation of the reaction product yields 3.6 parts of1-methylene-3,3-dipheny1cyclobutane boiling; at, 99.5- 106. C./0.22-0.44mm.

Analysis.Calcd. for C H C, 92.68% H, 7.32%; M01. wt., 220.3;Unsaturation, 0.0091 g. H /g. sample.

Found: C, 92.20%, 91.53%, 91.29%; H, 7.49%,,7.37%,

7.21%; M01 wt., 210, 210; Unsaturation, 0.0190, 0.0100 g. H g. sample.

Example WK-Preparation of 1-methylene-3-phenylcyclobutane H G-C-C HH,0=C0H,

tion, 0.0141, 0.0145 g. H /g. sample.

When the 1,1-diphenylethylene and styrene of'Ex amples XIII and XIV arereplaced with equivalent quantities of a-methylstyrene, and theprocedures of these examples repeated, there can be obtained 1-methyl-3-methylene-l-phenylcyclobutane and 2,6(or 7)-dimethyl- 2,6 (or7)-diphenyl-A9' Q-oct alin.- f

Example XV.Preparation of3-methylene-2,2-dimethylcyclobutanecarbonitrile A mixture of 132 partsof 3-methylbutadiene-l,2(1,1- dimethylallene), 344 parts of'acrylonitrile and 3.5 parts of phenothia'zine is heated at 200 C. for 8hours under autogenous pressure. The combined products from three suchruns are submitted to steam distillation. The organic phase of the steamdistillate is separated, dried over magnesium sulfate and freed ofunreacted starting materials by distillation at atmospheric pressure.The residue consists largely of a mixture of isomeric substitutedcyclobutanes and amounts to 403 parts. Distillation of this mixturegives 134 parts of ,3-methylene-2,2-dimethylcyclobutane-l-carbonitrile,B.P. 111 C./ 100 mm., 11 114502 "andf 200 parts of3-isopropylidenecyclobutane-lca'rbon i trile, B.P. 138 C./ 100 mm., n1.4691. The assigned jstructures of these compounds are based onelemental analysis, quantitative hydrogenation studies, and infraredandproton magnetic resonance spectra.

When the dimethylallene of Example XV is "replaced by equivalentquantities of l-methylallene, l,l-di-'n-butylall ejne andl-n-dodecylallene, there can be obtained 3-methylene-Z-methylcyclobutanecarbonitrile, 3-methyl'ene-- 2,2-di nbutyl-cyclobutanecarbonitrile and 3-methylene-2n-dQdecylcyclobutanecarbonitrile, respectively.

tetracar'boxylic anhydride A mixture of 98.1 parts of maleic anyhdride,20.0 parts of allene, 176 parts of benzene and 0.5 part of hydroquinoneis heated in a stainless steel vessel at 225 C. for 8 hours atautogenous pressure. The reaction mixture is filtered to separate 26.2parts of yellow solid from the liquid portion of the mixture. Theunreacted benzene and maleic anhydride are removed from the filtrate bydistillation. Distillation of the residue gives 21.3 parts of 3-methylenecyclobutane 1,2-dicarboxylic boils at 151-l57 C./22 mm.

Analysis.Calcd. for G l-I 0 C, 60.87%; H, 4.38%; M01. wt., 138.1 Sap.Equiv., 69.06; Quant. Hydrog, 0.0145 g. H /g. sample. Found: C, 60.69%,61.19, 60.81; H, 4.88%, 4.70, 4.72; M61. wt., 141,157; Sa'p. Equiv.,68.4, 68.3; Quant. Hydrog, 0.0186 g. H /g. sample.

anhydride that The infrared spectrum shows absorption at 5.4; and 5.6for the anhydride group and 5.95; and 11.0, for the terminal methylenegroup. t

vThe yellow solid .filtered out of the orginal reaction mixture melts at235-239" C. after sublimation. Recrystallization of this product fromethyl acetate yields small white needles of A-octa1in-2,3,6,7-tetracarboxylic anhydride, melting at 239-240 C.

Example X VII.-Preparation, of2-acetoxymethylmethylene-cyclobutdnecarbonitrile omooocnlcn=c=om+QHFCHCN naooooon, CN n ooooom H III A mixture of 168 parts of1-acetoxy-2,3-butadiene, 318 parts of acrylonitrile and 3.0,parts' ofphenothiazine is heated in a stainless steel reaction vessel underautogenous pressure at 200 C. for 8 hours. The liquid reaction productis' separated from a smallamount of amber solid and freed of 'unreactedacrylonitrile by distillation at atmospheric pressure. "Distillation ofthe residual oil,

Out Vol., ml. B.P./20 m" Individual fractions A-I are subjected toinfrared analysis. The infrared absorption spectrum of cut A showsabsorption at 5.95 and 11.20 microns, which is characteristic of theterminal methylene (C =CH group of 2acetoxymethyl-3-methylenecyclobutanecarbonitrile. These twobandsprogressively diminish in intensity from out A to cut F and are absentin cuts G-I. In addition all the distillation cuts, A-I, show bands at4.5 and 5.75 microns, which are characteristic of the cyano and estercarbonyl groups, respectively. It is evident from the,

wide boiling ranges of the crude reaction product and its dihydroderivatives that the reaction produces a mixture.

of compounds. The above infrared absorption data indicate that fractionsA-F contain a mixture of the cis and" trans isomers of2-acetoxymethyl-3-methylenecyclobutanecarbonitrile (formulas I and II inthe equation above), and the fractions G-I consist essentially of 3-(fl-acetoxyethylidene) cyclobutanecarbonitrile (Formula L'III in theequation above).

ellene-cyclopentadiene adduct t lzipto A mixture of 99.1 parts ofdicyclopentadiene (which at the operating temperature of 200 C. ispartially in the form of monomeric cyclopentadiene), 63 parts ofpentane, 3.0 parts of hydroquinone and 60 parts of allene is heatedunder autogenous pressure at 200 C. for 6 hours. The liquid reactionproduct is freed from pentaneandcyclopentadiene by distillation, andthere is obtained on fractional distillation at reduced pressure 69parts of allene-cyclopentadiene adduct boiling at 5556 C./95 mm. andhaving a refractive index, 12 of 1.4834.

Analysis.-Calcd. for C H C, 90.5%; H, 9.5%; Quant. Hydrog, 0.0377 g. H/g. sample. Found: C, 90.55%, 90.25%; H, 9.57%, 9.50%; Quant. Hydrog,0.0385, 0.0382 g. H /g. sample.

Example XIX.-Preparatin of dimethyl 2,6(0r 7)-dimethyl-A -0ctalin-3,7(or6) -dicorb0xylate 2CHg=C=OHz 2011;011:0516 O O CH;

C C-CH;

other.

and/or doooon,

A mixture of 225 parts of methyl crotonate, 30 parts of allene and 1part of hydroquinone is heated, for 8 hours at 200 C. under autogenouspressure. On distillation of the reaction mixture, after removal of,volatile material, there is obtained 35.2 parts of dimethyl 2,6(or 7)-dimethyl A octalin-3,7 (or 6) -dicarboxylate. On recrystallizationfrom a mixture of ethanol and Water, this product is a white, waxy solidmelting at 85-895 C.

Analysis.Calcd. for 0 1-1 0 C, 68.54%; H, 8.73%; M01. wt., 280.4. Found:C, 68.33%; H, 8.73%; M01. wt., 250.

As shown by the preceding examples, the products of this invention areof two classes. One class of these products comprises anymethylenecyclobutane in which the annular carbon opposite the one atwhich' the methylene group is attached (i.e., the carbon in the3-position when the methylene group is attached to the carbon in the1-position) carries an activating group, which activating group ischaracterized in that it is united to one annular carbon of thecyclobutane ring by a carbon which is in turn attached to another atomby a multiple bond. These products have the following general formula:

12 wherein X is COOH, COOR,

CN, CONH2, or 1; Y is H, alkyl, cycloalkyl, aryl, coon, coon,

CN, or CONHg; Z is H, COOH, COOR,

CN, CONH alkyl, or aryl; (X and Z taken together can be R is H, alkyl,phenyl or an acetoxy methyl radical; and R is selected from the groupconsisting of hydrogen and a lower alkyl radical. Thus, in addition tothe specific substituted methylenecyclobutanes mentioned above, theproducts of this invention include 3-methylenecyclobutanecarboxylicacid, 1-methyl-3-methylenecyclobutanecarboxamide,l-acetyl-3-methylenecyclobutane and3-methylenecyclobutanecarboxaldehyde. These particular compounds areprepared by reaction of allene with the following substituted ethylenes:acrylic acid, methacrylamide, and methyl vinyl ketone, respectively,under the conditions of the examples given above.

The second class of products of this invention oomprises any A -octalinhaving attached to the carbons in the 2 and S-positions of the octalinring at least one activating group, which activating group ischaracterized in that it is united to the annular carbon of the octalinring by a carbon which is, in turn, attached to another atom by amultiple bond, having attached to the carbons in the 6 and 7-positionsof the octalin ring the same number and kind of activating groups thatare attached to the 2 and 3 carbons, the annular carbons in the l, 4, 5and 8-positions of the octalin ring being unsubstituted. These productshave the following general formula:

Y/ Cfiz cz \Y wherein X is COOH, COOR,

CN, CONH or aryl; Y is H, alkyl, cycloalkyl, aryl, COOH, COOR,

another atom by a multiple bond. Thus, 3-methylene-2-phenylcyclobutanecarbonitrile,3-methylene-2,2-diethylcyclobutanecarbonitrile, and methyl3-methylene-2,2-din-octylcyclobutanecarboxylate can be preparedrespectively from the following reactions; acrylnitrile reacted withl-phenylallene, acrylonitrile reacted with 1,1-diethylallene, and methylacrylate reacted with 1,1-di-n-octylallene.

In place of hydroquinone and phenothiazine, other conventional additionof polymerization inhibitors which do not react with any of thereactants can be used in the process of this invention. Examples ofother inhibitors which are operable include copper resinate, thenaphthylamines and fi-naphthol.

In addition to the copolymers illustrated by Examples V and VI, thesubstituted methylenecyclobutanes of this invention can be copolymerizedwith a wide variety of polymerizable ethylenically unsaturatedcompounds. Thus, they can be copolymerized with olefins, both aliphaticmonoand diolefins, e.g., ethylene, propylene, butylene, and butadiene;vinyl and vinylidene halides, e.g., vinyl fluoride and vinylidenechloride; vinyl esters, e.g., vinyl acetate, vinyl benzoate, vinyllaurate; vinyl ketones, e.g., methyl vinyl ketone, and methylisopropenyl ketone; acrylic and methacrylic acids and their derivatives,such as esters, nitriles and anhydrides, e.g., ethyl acrylate, methylmethacrylate, acrylonitrile, methacrylic acid; butenedioic acids, andtheir derivatives, e.g., maleic and fumaric acids, their esters,nitriles, and anhydrides, substituted ethylenes, such astrifiuoroethylene, chlorotrifiuoroethylene and styrene.

The substituted methylenecyclobutanes of this invention are useful for awide variety of purposes. For example, they are useful for the formationof polymers by addition polymerization. They are particularly useful forcopolymerization with other copolymerizable monomers. The resultingpolymers are useful as adhesives, coating compostions, films and thelike. Those products of this invention having two functional groups,such as two carboxyl or carbalkoxy groups, are useful for modifyinghydroxyl-containing polymers, such as polyvinyl alcohol, cellulose, andstarch, and for modifying ethylene/ carbon monoxide polyamines. Theexocyclic double bond present in these methylenecyclobutanes is capableof reacting with many reagents that add to olefinic double bonds, forexample, mercaptans, hydrogen bromide and hydrogen.

The polysubstituted A -octa1ins of this invention are also useful formany purposes. For example, they are useful for reacting withcomplementary bifunctional reactants to form condensation polymers.These condensation polymers are useful as adhesives, coatingcompositions, films, and the like. The polysubstituted A octalins havingcarboxyl or carbalkoxyalkyl groups are useful for the formation of suchcondensation polymers as polyesters, polyamides and polyirnides. The Aoctalins are also useful as chemical intermediates. For example, theycan be hydrogenated to the corresponding saturated ring compounds by useof nickel alloy skeleton catalysts, and the polycyano compounds can behydrogenated in the presence of carbon-supported palladium catalysts tothe corersponding polyamines. Ester groups on the A -octalins can behydrogenated to hydroxyl groups by use of copper chromite catalysts.

As many apparently widely different embodiments of this invention may bemade Without departing from the spirit and scope thereof, it is to beunderstood that this invention is not limited to the specificembodiments thereof except as defined in the appended claims.

.14 Iclaimz. x 1. 3-methy1enecyclobuta.necarbonitrile. 2.3-methylenecyclobutane-1,2-dicarboxylic anhydride. 3,11Aprocess forpreparing a metliylene cyclobutane which comprises heating an allene ofthe'formula R! in which R is selected from the group consisting ofhydrogen, alkyl, phenyl, and acetoxymethyl with a substituted ethylenehaving attached to one of the doubly bonded carbons of the ethyleniclinkage, a member of the group consisting of II COOH, 000R, O-R, CN,CONH,

II COOH, 000R, C--R, ON, CONE:

and aryl wherein R is selected from the group consisting of hydrogen anda lower alkyl radical, in the presence of a polymerization inhibitor, toa temperature of 250 C.

5. A process for preparing a methylene cyclobutane which comprisesheating in the absence of a polymerization initiator, a mixture ofallene and acrylonitrile to a temperature of 150-250 C.

6. A methylene cyclobutane of the following structural formula where Xis a radical selected from the group consisting of 0 00013., COOR, -R,ON, CONE and aryl; Y is selected from the drogen, alkyl, cycloalkyl,aryl,

group consisting of by- I COOH, 000R, (|]R, CN, and CONE; Z is selectedfrom the group consisting of 0 H, GooH, 000R, i l-R, ON, OONH, alkyl andaryl and X and Z jointly represent R is selected from the groupconsisting of hydrogen, alkyl, phenyl and an acetoxymethyl radical, andR is selected from the lower alkyl radical.

(References on following page) group consisting of hydrogen and a 15 16References Cited in the file of this patent I OTHER REFERENCES UNITEDSTAT S-PATENTS 1 Coflmane1. a1;: J .1 C.S;, v01. 71', p. 496 1941,944,731 D iels et all Jan. 23,1934 33 3???? 5 P9 567 (pubhshed2,406,657 BitleretaL- Aug.27, 1946 3 r 2,537,873 Allen et a1. Ian. 9,1951 2,560,119 McCaslin et a1. July 10, 1951 2,592,301 Linville Apr. 8,1952 UNITED STATES PATENT OFFICE Certificate of Correction o Patent No.2,914,541 November 24, 1959 Harry Norman Oripps It is hereby certifiedthat error appears in the printed specification of the above numberedpatent requiring correction and that the said Letters Patent should readas corrected below.

Column 7 lines 2 1 to 26, Example X, the left-hand portion of theformula should appear as shown below instead of as in the patent:

cm=o=oH,+o,H,ooc-c11 nc-coocim column 8, lines 13 to 16, Example XII,the right-hand portion of the formula should appear as shown belowinstead of as in the patent:

same column 8, line 72, for C, 91.69% read --C, 91.67 column 9, line 3,for

these read those-; column 10, lines 14 to 21, inclusive, Example XVII,Formula II should appear as shown below Instead of as in the patent:

HlCOOOCH: H

H3O same column 10, line 3?, for 61. 7 1% read --6.7l%; column 13, line9, for acrylnitrle read arylon1tr1le; km 14, strike out of; line 67, forcorersponding rea -correspon 1ng.

Signed and sealed this 5th day of J uly 1960.

Attest KARL H. AXLINE, ROBERT c. WATSON, Attestz'ng Officer.Omrwm'ssioner of Patents.

6. A METHYLENE CYCLOBUTANE OF THE FOLLOWING STRUCTURAL FORMULA